Abstract

In current Xray CT scanners, tomographic reconstruction relies only on directly transmitted photons. The models used for reconstruction have regarded photons scattered by the body as noise or disturbance to be disposed of, either by acquisition hardware (an anti-scatter grid) or by the reconstruction software. This increases the radiation dose delivered to the patient. Treating these scattered photons as a source of information, we solve an inverse problem based on a 3D radiative transfer model that includes both elastic (Rayleigh) and inelastic (Compton) scattering. We further present ways to make the solution numerically efficient. The resulting tomographic reconstruction is more accurate than traditional CT, while enabling significant dose reduction and chemical decomposition. Demonstrations include both simulations based on a standard medical phantom and a real scattering tomography experiment.

Notes

Acknowledgments

We thank V. Holodovsky, A. Levis, M. Sheinin, A. Kadambi, O. Amit, Y. Weissler for fruitful discussions, A. Cramer, W. Krull, D. Wu, J. Hecla, T. Moulton, and K. Gendreau for engineering the static CT scanner prototype, and I. Talmon and J. Erez for technical support. YYS is a Landau Fellow - supported by the Taub Foundation. His work is conducted in the Ollendorff Minerva Center. Minerva is funded by the BMBF. This research was supported by the Israeli Ministry of Science, Technology and Space (Grant 3-12478). RG research was partially supported by the following grants: Air Force Contract Number FA8650-17-C-9113; US Army USAMRAA Joint Warfighter Medical Research Program, Contract No. W81XWH-15-C-0052; Congressionally Directed Medical Research Program W81XWH-13-2-0067.